Yu was born in 1975 in Zhejiang, China. In 1997, Yu graduated from the Department of Biology of Peking University in Beijing. She then went to the United States to continue her study, and obtained PhD from the University of Pennsylvania in 2003.
In 2003, Yu joined James Thomson's lab at UW–Madison as a researcher. Yu is an important leader in developing novel method of reprogramming adult cells to create pluripotent cells which are not from embryonic stem cells. In Nov 2007, a study done by Yu et al.  achieved the production of induced pluripotent stem cells by genetic reprogramming of human dermal fibroblasts (from a baby's foreskin). This groundbreaking result was published in Science.
- UW–Madison: University Communications: Introduction of Junying Yu and her work, including photos
- UW–Madison News: November 2007, a new study led by UW scientist Junying Yu and conducted in Thomson’s lab achieves genetic reprogramming of human skin cells to create cells indistinguishable from embryonic stem cells.
- Yu J, Vodyanik MA, et al. | Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells | Science doi:10.1126/science.1151526 | PMID 18029452
- UW–Madison scientists guide human skin cells to embryonic state
- Person of the Year 2007: Junying Yu, James Thomson and Shinya Yamanaka; TIME